ANTICOAGULATION prescribing rates in rural and remote Western Australia are approaching the global average thanks to increasing acceptance of non-vitamin K antagonist oral anticoagulants (NOACs), according to research published in the MJA.

Because of its highly variable metabolism, warfarin requires regular monitoring to ensure that its blood levels remain in the therapeutic range at least 55% of the time . In a country where 29% of the population lives in rural or remote areas, access to health services can be problematic in some parts of Australia. For patients on warfarin, that can mean less than optimal anticoagulant therapy.

Researchers from the Royal Perth Hospital, Bunbury Regional Hospital, South West Health Campus, and the University of Western Australia had three main aims:

to determine the use of different anticoagulation therapies in rural Western Australia;

to gather preliminary data on anticoagulation therapy safety and efficacy

They conducted a retrospective cohort study of patients hospitalised with a principal diagnosis of atrial fibrillation/flutter (AF) or venous thromboembolism (VTE) during 2014–2015 in four hospitals serving two-thirds of the rural population of WA. They identified 609 patients with an indication for anticoagulation therapy recorded in hospital discharge summary for index admission.

Dr Jamie Bellinge, a research fellow at Royal Perth Hospital, and a PhD candidate in cardiology at UWA, told MJA InSightin an exclusive podcast, that the overall rates of prescription of NOACs and warfarin were similar (34% v 33%), but that NOACs were more often prescribed for patients with AF (56.0% v 42.2%) and that warfarin was more often prescribed for patients with VTE (48% v 29%).

“We think that difference is because VTE is a relatively new indication for the use of NOACs,” Dr Bellinge said. “NOACs have been used for stroke prevention in VTE only for about 3 years. That lag is likely to be [the reason] for slower uptake for that indication.”

The researchers also found that 31% of patients with indications for anticoagulant therapy walked away from hospital without a prescription for either warfarin or NOACs.

The researchers also found that warfarin was prescribed for 38% of patients who lived locally — that is in the town where their hospital or GP was based — and a NOAC was prescribed for 31%. For non-local patients, the respective proportions were 29% and 36%. Patients from outside the region were more often prescribed a NOAC than warfarin (43% v 9%).

“This makes sense,” Dr Bellinge said. “Patients in the town where they were admitted to hospital are more likely to get warfarin than NOACs because they have easier access [to regular monitoring].

“As patients live in more remote settings, they tended to be prescribed NOACs.

“This is promising because it suggests that rural practice is tending towards accepting the safety and tolerability of NOAC therapies. In terms of safety, although a lot of the data comes out of urban settings, seems to have translated reasonably well into rural areas. Rural physicians seem to be [becoming] comfortable with prescribing NOACs.”

During the course of the study, bleeding events were more common among patients treated with warfarin than those treated with a NOAC (10% v 4%).

“That’s also promising, and may assist in promoting the prescribing of NOACs in rural cohorts,” Dr Bellinge said.

The transfer of evidence-based knowledge to clinical settings in remote and rural areas “remains difficult”, the researchers wrote.

The issue for rural doctors, isn’t that they are unaware of NOACs and their benefits, it is their ongoing concern of the lack of a reversal agent given the tyrany of distance. There is only one reversal agent for dabigatran and even then it’s unlikely to be available rurally due to cost of keeping it stocked. Until there is universal access to a cheap reversal agent like warfarin has, the rural community of doctors and patients will continue to be reluctant to fully endorse NOACs due to potential higher risk of uncontrollable haemorrhage in rural areas where trauma rates are naturally higher anyway.

Before the introduction of reversal agents, the NOAC studies with AF showed that hospital outcomes for patients with major bleeding were actually better for NOAC patients rather than those on Warfarin. Also, the worst bleeding complication, intra-cranial, is much less likely on NOACs than Warfarin – reversal usually doesn’t help in this circumstance. Unusual anecdotes show the advantage of reversal agents, but for the majority, NOACs are preferrable.